That's interesting - that with Salt, one can experience a more intense sensation at the sides of the tongue !
Well written post - some people may be surprised to learn about the papillae. The Author suggests you EXPLORE MORE by reading his article here : >> https://steemit.com/science/@timsaid/life-explorers-the-human-senses-part-iv-taste
Fun experiment to try - just recall to put the salt @ end of your tongue.